We’re about an hour and fifteen minutes into our most recent Coast to Canopy episode, and we’ve been having fun talking about, looking at, and holding snakes. Then my cohost, Regan McCarthy, mentions Burmese pythons. Our celebration of Florida’s diverse serpents takes a serious turn: It turns out that the pythons may have unleashed an invasive parasite that is wiping out native snake populations.
“I’m glad you brought up Burmese pythons,” says Kim Sash. Kim is the Biological Monitoring Coordinator at Tall Timbers Research Station and Land Conservancy. “Because I think this is really important for our viewers to learn about the non-native pentastomes, that is a species that was probably brought to the US in Burmese pythons, when they were brought to the US.”
Burmese pythons are an invasive species. They came to the US as pets, and escaped captivity to establish a population in the Florida Everglades. They have no natural predators in Florida, and they are much larger than native snakes. The largest Burmese python caught in Florida was 18 feet long. Our largest native, the eastern indigo snake, can reach 8.6 feet, less than half as long as the longest python.
Burmese pythons have decimated mammal populations in south Florida, from rabbits to deer. Now, they’re affecting snake populations state-wide thanks to a parasite that likely hitchhiked here inside their lungs.
Raillietiella orientalis, invasive snake lungworm
It’s called a lungworm, and it looks like a white worm. Raillietiella orientalis is a type of crustacean of the subclass Pentastomida, a parasite that lives inside the lungs of reptiles and amphibians.
Kim explains how the pentastome’s life cycle has helped it spread beyond the range of its original host.
“Burmese pythons, they will poop out pentastome eggs. The cockroach will eat that Burmese python poop. Then, some intermediate host, usually a frog or a lizard will eat that cockroach, and the pentastome will hatch out and live inside that intermediate host. Not really harm it, but just live inside of it. We’re not entirely sure yet what it does to that intermediate host.
“Then that lizard or frog gets eaten by a [native] snake. And so, then the pentastome will migrate to the lungs of that snake. Now, when we think about a Burmese python, everybody thinks about a big fourteen foot snake. So, these crustaceans… can get actually very large because [Burmese python] lungs are large. Now, our native snakes, much smaller species, they have much smaller lungs, of course.
“And so, what’s happening is these pentastomes are actually suffocating these snakes to death, literally to death. We’ve lost about 90% of our pigmy rattlesnakes down in the Everglades because of this.”
Marching North Through Florida
The invasive snake lungworm has been expanding its range northward, reaching as far north as Jacksonville. It has also been spotted in a handful of panhandle counties, and as far north as Illinois. One way that it’s hopping into places not connected to its range is through small, nonnative lizards.
“One of the things that I know that FWC (Florida Fish and Wildlife Conservation Commission) has been working on is trying to tamp down some of the movement,” Kim says. “Brown anoles are also an exotic species that live in Florida, so they can be an intermediate host for this. And brown anoles are often trapped, and then people ship them in Florida to other areas of the country, for feeding snakes usually.”
The parasite has been found in at least 18 native snake species; in our podcast, FWC Fish and Wildlife Research Institute research associate Pierson Hill told us Florida has 66 species. There is currently no remedy. For now, FWC and snake researchers are monitoring the spread, and asking for help from the public.
Reporting Raillietiella orientalis in Florida
The Snakeworm Lungworm Alliance and Monitoring (SLAM) is a collective made up of snake researchers across the state. They’re working to better understand the invasive pentastomes and how they spread. A first step is monitoring.
SLAM is asking the public to send information about sightings, and photos to their email or Instagram accounts:
Instagram: slam.conservation
Gmail: slam.conservation@gmail.com
You can also upload photos to the iNaturalist app.
The Best Hope for Native Snakes: Florida’s Intact Habitats?
While there have been no solutions to date, Pierson Hill feels that Florida’s best hope might lie in places like the Florida panhandle, where hundreds of thousands of acres of conservation land make plant and animal populations more resilient.
“A lot of the time in these situations, you can just only hope that we have robust enough populations,” Pierson says, “that they can adapt and become resilient and just learn to live with the new parasite. That’s one of the downfalls of an increasingly fragmented landscape, is that we have very small, fragile populations of even common species left that don’t have enough individuals and enough genetic diversity to be able to tolerate these new threats.
“And, so those are the populations you lose first are kind of isolated small populations. And, but yeah, it’s kind of a wait and see.”
Watch the full Coast to Canopy episode on the snakes of Florida
Kim and Pierson brought in an eastern kingsnake, grey ratsnake, Florida pine snake, western hognose snake, and striped salt marsh snake, and we talked about everything from the Florida’s diverse snake species to what to do when you encounter venomous snakes.
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